1. Field of the Invention
The present invention relates to a structure for installing a cabin to a construction machine such as a motor grader, a hydraulic shovel, a wheel loader, and so on.
2. Description of the Related Art
When a construction machine is transported by being mounted on a loading space of a truck, with its cabin installed on the body of the machine, the whole height of the truck may exceed a height limit for transportation due to an existence of the cabin.
In particular, when a motor grader which is so constructed as to have a tall cabin so that an operator can stand in the cabin during operation is transported on a loading space of a truck, the whole height of the truck exceeds a height limit for transportation.
In this case, the motor grader is transported after removing the cabin, which is installed on the body of the motor grader at a construction site. Such installation and removing works are complicated and troublesome.
There has been a known installation structure in which a lower housing and an upper housing are engaged with each other to form a cabin such that the housings are movable in the vertical direction and the lower housing is attached to a machine body, as is disclosed in Japanese Utility Model Laid-open Publication No. 4-125921.
According to the installation structure described above, the height of the cabin is decreased by moving downwards the upper housing, and the height of the cabin is increased by moving upwards the upper housing. Therefore, the height of the cabin can be increased when an operator rides in and operates the machine, and the height can be decreased during transportation of the machine so that the machine does not exceed the height limit for transportation.
Thus, according to the installation structure of the cabin as described above, the stroke of vertical movement of the upper housing is substantially half of a maximum height of the cabin, and therefore, the cabin can only be lowered substantially to the half of the maximum height of the cabin obtained when the upper housing is moved to the uppermost limit.
Therefore, in case where the height of the cabin (or the maximum cabin height) is large like a large-sized motor grader, the height sometimes exceeds a height limit for transportation even if the upper housing is moved to its lowermost position.
Further, in this structure, a door for opening and closing an entrance/exit of the cabin is divided into upper and lower parts and the upper door part is connected to the lower door part such that the upper door is movable in the vertical direction. Therefore, when the upper housing is moved downwards, the door cannot be opened or closed because the door parts are layered inside and outside. If the door can be opened or closed, the inside and outside door parts must be opened or closed one after another, and the structure of the door parts and the installation structure of the cabin are thus complicated.